1. Field of the Invention
Embodiments of the present invention generally relate to a magnetic read sensor and a method for its manufacture.
2. Description of the Related Art
Magnetic read sensors are used in hard disk drives to read bits of data from the hard disk drive. An example of a magnetic read sensor is shown in FIG. 1. The magnetic read sensor includes a first shield layer 102 and a sensor structure including a pinned layer 106, a barrier layer 108, a free layer 110 and a cap layer 112. The top of the first shield layer 102 and the sidewalls of the sensor structure are covered with an insulating layer 114. A hard bias layer 116 and a hard bias capping layer 118 are then formed over the insulating layer 114. A top lead layer 120 and second shield layer 104 are then formed over the hard bias capping layer 118, hard bias layer 116, insulating layer 114 and cap layer 112.
The insulating layer 114 may comprise aluminum oxide and is used to electrically separate first shield layer 102 from the second shield layer 104 in areas away from the sensor junction. The sensor junction is the area where the insulating layer 114 separates the sensor structure from the adjacent hard bias layer 116 that magnetically biases and stabilizes the sensor structure.
The insulating layer 114 typically is deposited by an atomic layer deposition (ALD) process. However, ALD has certain drawbacks. One of the drawbacks is sensor structure edge damage. Because ALD involves introducing an oxidizing gas such as water vapor or oxygen into the chamber during the deposition process, portions of the sensor, such as the barrier layer 108 and pinned layer 106, oxidize when exposed to the oxidizer. Thus, the edges or sidewalls of the sensor structure are damaged due to oxidation. Another drawback is the oxygen from the ALD process diffuses into the barrier layer 108, which increases the RA value (i.e., resistance times area).